<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <style>
        div{
            width: 200px;
            height: 200px;
            color: black;
        }

        .ball{
            background-image: radial-gradient(circle, yellow 5%, transparent 60% 100%);
        }
    </style>
    <div class="ball"></div>
</body>
</html>